1. Technical Field
The present invention relates to a multifunctional time measurement device having hands, and to a time measurement method.
2. Background Art
Conventionally available as a multifunctional time measurement device having hands is, for example, a timepiece having an analog-display chronograph function.
Such a timepiece has, for example, a chronograph hour hand, a chronograph minute hand, and a chronograph second hand for chronograph purposes, and starts time measurement in response to the push of a start/stop button provided therein, so that the chronograph hour hand, the chronograph minute hand, and the chronograph second hand turn. When the start/stop button is pushed again, time measurement is finished, and the chronograph hour hand, the chronograph minute hand, and the chronograph second hand stop, thereby indicating the measured time. At the push of a reset button provided in the electronic timepiece, the measured time is reset, and the chronograph hour hand, the chronograph minute hand, and the chronograph second hand return to zero positions (hereinafter referred to as “return to zero”).
In a reset method, the hands are returned to zero by being moved quickly by a chronograph motor when the timepiece is of an electronic type, and are mechanically returned when the timepiece is of a mechanical type. Some of such mechanical return mechanisms have a safety mechanism for preventing a return operation from being performed due to an inadvertent press of the reset button during time measurement. This safety mechanism is a mechanism that disables time measurement from being reset after the start thereof, and enables time measurement to be reset after the stop thereof.
In addition, the timepiece has a function of automatically stopping the chronograph hour hand, the chronograph minute hand, and the chronograph second hand at, for example, the hand positions at the start of time measurement when the maximum measurement time is over. This function can prevent power from being consumed in vain even when the start/stop button fails to be pushed during time measurement.
The above-described safety mechanism is configured to mechanically and alternatively repeat the return impossible state and the return enabling state every time the start/stop button is operated. Since such a safety mechanism has been provided in mechanical timepieces hitherto, there is no special problem. When an electronic timepiece is provided with a mechanical return mechanism and a safety mechanism, however, the recognition of the return impossible state and the return possible state in a control circuit of the timepiece and the recognition of the return impossible state and the return possible state in the safety mechanism are sometimes reversed.
For example, as shown in FIG. 22, when a start signal is output in response to the push of the start/stop button at a point T1, measurement recognition (motor pulse output) of the control circuit is started, and the safety mechanism is put into the return impossible state. Subsequently, when the power-supply voltage falls below the operating voltage required for the operation of the control circuit at a point T2 due to discharging or for other reasons, measurement recognition (motor pulse output) of the control circuit is stopped, whereas the safety mechanism is held in the return impossible state. These states are maintained even after the power-supply voltage is recovered above the above-described operating voltage at a point T3 by charging or by other methods.
Therefore, when a start signal is output at the push of the start/stop button at a subsequent point T4, measurement recognition (motor pulse output) of the control circuit is started, whereas the safety mechanism is put into the return possible state. Furthermore, when a stop signal is output at the push of the start/stop button at a subsequent point T5, measurement recognition (motor pulse output) of the control circuit is turned off, whereas the safety mechanism is put into the return impossible state.
For this reason, when a reset signal is output due to an inadvertent push of the reset button between the point T4 and the point T5, since the safety mechanism is in the return possible state, a returning operation is performed during time measurement. Even when a reset signal is output at the push of the reset button at a point T6, and the reset recognition of the control circuit is turned on, a returning operation is impossible though time measurement has been stopped, because the safety mechanism is in the return impossible state. In this way, when the chronograph function abnormally stops, the recognition by the control circuit and the state of the safety mechanism are reversed in the chronograph start/stop and reset operations.
An object of the present invention is to solve the above problems, and to provide a time measurement device and method in which an electric operating state and a mechanical operating state can always coincide with each other.
Conventionally available as a multifunctional time measurement device having hands is, for example, an electronic timepiece having an analog-display chronograph function.
Such an electronic timepiece has, for example, a chronograph hour hand, a chronograph minute hand, and a chronograph second hand for chronograph purposes, and starts time measurement in response to the push of a start/stop button provided therein, so that the chronograph hour hand, the chronograph minute hand, and the chronograph second hand turn. When the start/stop button is pushed again, time measurement is finished, and the chronograph hour hand, the chronograph minute hand, and the chronograph second hand stop, thereby indicating the measured time. At the push of a reset button provided in the electronic timepiece, the measured time is reset, and the chronograph hour hand, the chronograph minute hand, and the chronograph second hand return to zero positions (hereinafter referred to as “return to zero”).
In a reset method, the hands are returned to zero by being moved quickly by a chronograph motor when the timepiece is of an electronic type, and are mechanically returned when the timepiece is of a mechanical type. Some of such mechanical return mechanisms have a safety mechanism for preventing a return operation from being performed due to an inadvertent press of the reset button during time measurement. This safety mechanism is a mechanism that disables time measurement from being reset after the start thereof, and enables time measurement to be reset after the stop thereof.
Some of such electronic timepieces have a chronograph hand for measuring time more finely than the chronograph second hand and showing time in the minimum measurement unit, for example, a chronograph ⅕-second hand, or a chronograph 1/10-second hand. Since large electric power is needed to continuously move the chronograph hand for showing time in the minimum measurement unit, however, the hand is set to stop its movement after a predetermined time elapses from the start of measurement. When time measurement is stopped, the hand is moved quickly by the motor to the hand position indicating time finely, so that reading the measured time is allowed.
In addition, the electronic timepiece has a function of automatically stopping the chronograph hour hand, the chronograph minute hand, and the chronograph second hand at, for example, the hand positions at the start of time measurement when the maximum measurement time is over. This function can prevent power from being consumed in vain even when measurement fails to be stopped by pushing the start/stop button during time measurement.
In the electronic timepiece provided with the chronograph thus having the mechanical return function and the function for preventing return during time measurement, even when the maximum measurement time is over during time measurement and the movement of the chronograph hour hand, the chronograph minute hand, and the chronograph second hand is automatically stopped, this state appears to the user that the chronograph hour hand, the chronograph minute hand, and the chronograph second hand have been returned to zero because the hands are stopped at, for example, the time measurement start positions. Even when the user attempts to start time measurement by pushing the start/stop button in this state, since time measurement has been already stopped halfway by the automatic stop function, it is merely mechanically stopped. That is, the operation the user intends to perform and the actual operation of the electronic timepiece do not coincide with each other. That is, the user loses a good timing of measurement. Moreover, the user may falsely recognize that the electronic timepiece is out of order.
Furthermore, when the chronograph hand for finely measuring time is stopped after a predetermined time has elapsed, it is impossible to read time in the minimum measurement unit during measurement, and false recognition that the timepiece is out of order is apt to be made.
An object of the present invention is to solve the above problems, to provide a time measurement device and method in which the user is informed that time measurement is automatically stopped after the maximum measurement time has elapsed from the start thereof, and is urged to perform a stop operation and a reset operation in the next use so as not to lose a good timing of measurement, and to provide a time measurement device and method that allows the elapsed time to be known in the minimum measurement unit at any time during time measurement and that provides excellent usability.
Conventionally available as a multifunctional time measurement device having hands is, for example, an electronic timepiece having an analog-display chronograph function.
Such an electronic timepiece has, for example, a chronograph hour hand, a chronograph minute hand, and a chronograph second hand for chronograph purposes, and starts time measurement in response to the push of a start/stop button provided therein, so that the chronograph hour hand, the chronograph minute hand, and the chronograph second hand turn. When the start/stop button is pushed again, time measurement is terminated, and the chronograph hour hand, the chronograph minute hand, and the chronograph second hand stop, thereby indicating the measured time. At the push of a reset button provided in the electronic timepiece, the measured time is reset, and the chronograph hour hand, the chronograph minute hand, and the chronograph second hand return to zero positions (hereinafter referred to as “return to zero”).
Such an electronic timepiece has a split function in which the chronograph hour hand, the chronograph minute hand, and the chronograph second hand are stopped by the push of the reset button during time measurement while time measurement continues, are moved quickly by a continuously measured time when the reset button is pushed again, and subsequently turn in an ordinary manner. This function allows the user to visually recognize the measured time with precision at a plurality of points during time measurement, and, for example, to record the measured time.
In addition, the electronic timepiece has a function of automatically stopping the chronograph hour hand, the chronograph minute hand, and the chronograph second hand at, for example, the hand positions at the start of time measurement when the maximum measurement time is over. This function can prevent power from being consumed in vain even when the start/stop button fails to be pushed during time measurement.
Some of these types of electronic timepieces have power generators. In such an electronic time piece, for example, the user ordinarily wears the electronic timepiece and gives small vibrations or the like thereto, thereby causing the power generator provided inside the electronic timepiece to generate power. A secondary battery or the like is charged with the generated power so as to be used as a power-supply battery for the electronic timepiece.
In the above-described electronic timepiece having a chronograph, however, time measurement sometimes stops halfway due to a fall in voltage resulting from a shortage of charge capacity in the power-supply battery. In such a case, even when the user attempts to charge the power-supply battery by generating power by the power generator in a stopped electronic timepiece, it is impossible to immediately ensure sufficient charge capacity. When the chronograph is driven again in such a state in which the charge capacity in the power-supply battery is insufficient, a more power is consumed by the chronograph than the amount of power generated by the power generator, so the operation of the electronic timepiece is stopped again. Even if measurement is restarted when the voltage of the power-supply battery rises from this state, the indicated measured time, is inaccurate, and the user may read an incorrect measured time.
An object of the present invention is to solve the above problems, and to provide a time measurement device and method in which, even when the user is measuring time with the time measurement device having a time measuring function and the operation of the time measurement device is stopped due to the fall of voltage resulting from a shortage of charge capacity in a power-supply battery, the measurement operation does not stop immediately after restarting measurement since it is not performed until the power-supply battery is recharged by a power generator and the voltage or capacity for allowing reliable measurement is obtained, in which wasteful power consumption is prevented because the measurement operation is not started until the operation (input) is performed by the user even when the voltage or capacity reaches the voltage or charge for allowing reliable operation, and in which inaccurate measured time that the user does not intend is not indicated.